Survival rates for pediatric acute lymphoblastic leukemia (ALL) now exceed 80%. With this growing population of long-term survivors comes recognition that a considerable proportion experience one or more significant late effects. For children undergoing central nervous system (CNS) treatment, common late effects include neurocognitive impairment and neurobehavioral problems. Although these problems first manifest as subtle difficulties with attention and processing speed, they can evolve into deficits in higher order brain functions that significantly impact functional skills in a subset of long-term survivors. There currently is no method to accurately identify patients at greatest risk for these long-term behavioral and neurocognitive problems. Through this proposal, this study plans to utilize existing data collected during acute treatment to identify predictors of long-term neurocognitive and brain maturation outcomes. The study also proposes to collect data on attention-deficit/hyperactivity disorder (ADHD) and associated comorbidities, higher order executive functions, and structural and functional brain imaging in survivors who are at least 8 years of age and greater than 5 years from diagnosis.